This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Dysfunction of the neuronal microcircuits in the prefrontal cortex is believed to underline the pathogenesis of some major neuropsychiatric disorders, such as schizophrenia. Generation and maintenance of persistent neuronal activity is one of essential features of these prefrontal circuits underlying many prefrontal functions, including working memory. The aims of this project are to investigate 1) the basic synaptic transmission properties in prefrontal microcircuits, 2) synaptic plasticity, especially spike timing-dependent plasticity (STDP), and its interaction with persistent neuronal activity, 3) the modulatory effects of dopaminergic input and underlying molecular mechanisms.